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Project Trial-wise SBHM Coefficients to Scalar Amplitudes

Source: R/sbhm_project.R
sbhm_project.Rd

Given trial-wise coefficients in the shared basis (rxntrialsxV) and the voxel-specific matched library coordinates alpha_hat (rxV), compute scalar amplitudes per trial and voxel via least-squares projection: a = (alpha' beta) / (alpha' alpha).

Usage

sbhm_project(beta_rt, alpha_hat)

Arguments

beta_rt

3D array of shape r x ntrials x V containing per-trial coefficients in the SBHM basis (as returned by OASIS with K=r, reshaped).

alpha_hat

Numeric matrix rxV of matched library coordinates per voxel (e.g., sbhm_match()$alpha_hat). These should be in the same coordinate system as beta_rt (unwhitened, not L2-normalized) for interpretable amplitudes.

Value

Numeric matrix ntrials x V of scalar amplitudes.

Examples

if (FALSE) { # \dontrun{
  r <- nrow(alpha_hat)
  ntrials <- nrow(beta_mat) / r
  beta_rt <- array(beta_mat, dim = c(r, ntrials, ncol(beta_mat)))
  amps <- sbhm_project(beta_rt, alpha_hat)
} # }